libnl3 ... missing feature for retrieving cached address objects?

[David Sommerseth]

On 09/09/13 17:57, David Sommerseth wrote:
> 
> Hi,
> 
> I'm doing some massive updates to python-ethtool, which uses libnl to
> retrieve information about network and hardware configurations.  The use
> of libnl-1 was added quite a long time ago to especially implement IPv6
> support.  I'm now doing a lot of changes to improve the overall code and
> simplify the implementation.
> 
> In this process, I found rtnl_addr_get() too specific, as I want to
> retrieve the IP address for a specific link.  From what I could see,
> rtnl_addr_get() will always filter based on the struct nl_address object
> passed to it and match against the given address.  This is too strict
> for my use case.  Further I couldn't find any other obvious solutions to
> extract this information, except traversing all objects using
> nl_cache_foreach_filter() and a callback function.
> 
> So I propose a new function - rtnl_addr_get_index() (patch attached)
> which is a simplified rtnl_addr_get() function.  On my slight testing,
> this seems to work quite well.
> 
> However, I'm not sure if I'm overlooking something here?  Or is there a
> better or simpler approach?

Okay, I was obviously too quick on my testing.  This approach doesn't
fully resolve my challenge.  I just discovered links with multiple IP
addresses will not retrieve all IP addresses with the approach the patch
introduces.

The solutions seems to be to use rtnl_addr_set_ifindex() on an otherwise
"empty" rtnl_addr object together with nl_cache_foreach_filter() and a
callback function.

If anyone have an easier approach, I'm all ears.

Otherwise, sorry about the noise!


--
kind regards,

David Sommerseth